Flux-dependent electric field changes in semi-insulating CdZnTe

Franc, J.; Dědič, V.; Zázvorka, Jakub; Hakl, M.; Grill, R.; Sellin, P.J.

doi:10.1088/0022-3727/46/23/235306

Cited by 19 publications

(12 citation statements)

References 13 publications

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“…We observed a similar behavior in other CZT sample in our Ref. 12, which we explained as due to optically induced transitions of electrons from valence band to a midgap level at 0.75 eV. Then we partially depolarized the sample using 640 nm red light.…”

Section: Study Of Deep Levels Participating In Polarization and Desupporting

confidence: 82%

“…The setup and the experimental procedure is in detail described in our Ref. 12. The results of the measurement at energies 1.2-1.8 eV are shown in Fig.…”

Section: A Infrared Spectral Scanningmentioning

confidence: 99%

“…[8][9][10][11]. In our recent paper, 12 we have applied the technique of infrared spectral scanning combined with the Pockels electro-optic effect to investigate the energy of deep levels responsible for depolarization with infrared light and to look for an optimal energy range for depolarization.…”

Section: Introductionmentioning

confidence: 99%

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Temporal and temperature evolution of electric field in CdTe:In radiation detectors

Dědič

Zázvorka

Rejhon

et al. 2014

Journal of Applied Physics

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We have studied the possibility of above bandgap light induced depolarization of CdZnTe planar radiation detector operating under high flux of X-rays by Pockels effect measurements. In this contribution, we show a similar influence of X-rays at 80 kVp and LED with a wavelength of 910 nm irradiating the cathode on polarization of the detector due to an accumulation of a positive space charge of trapped photo-generated holes. We have observed the depolarization of the detector under simultaneous cathode-site illumination with excitation LED at 910 nm and depolarization above bandgap LED at 640 nm caused by trapping of drifting photo-generated electrons. Although the detector current is quite high during this depolarization, we have observed that it decreases relatively fast to its initial value after switching off the depolarizing light. In order to get detailed information about physical processes present during polarization and depolarization and, moreover, about associated deep levels, we have performed the Pockels effect infrared spectral scanning measurements of the detector without illumination and under illumination in polarized and optically depolarized states. V C 2015 AIP Publishing LLC. [http://dx

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Section: Study Of Deep Levels Participating In Polarization and Desupporting

confidence: 82%

“…The setup and the experimental procedure is in detail described in our Ref. 12. The results of the measurement at energies 1.2-1.8 eV are shown in Fig.…”

Section: A Infrared Spectral Scanningmentioning

confidence: 99%

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Temporal and temperature evolution of electric field in CdTe:In radiation detectors

Dědič

Zázvorka

Rejhon

et al. 2014

Journal of Applied Physics

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“…Previously, for a study of the polarization and de-polarization processes in detectors, we developed the method of infrared spectral scanning (IRSS) exploiting the Pockels effect, which was tested on several CZT and CdTe samples [9,10,18]. The IRSS is based on measurements of the electric field profiles in the biased sample, which is excited by light with a fixed wavelength causing the polarization (represented by an LED at 940 nm in this paper).…”

Section: Methodsmentioning

confidence: 99%

“…The internal electric field study by Pockels effect measurements and the pulse height spectrum analysis using a standard spectroscopic setup were used for the characterization of the IR de-polarization phenomena. In some measurements, the LED at 940 nm (∼1.32 eV) instead of X-rays was used, because it was previously shown [9] that the IR light with a slightly below the bandgap wavelength (around 900–950 nm in the case of CZT) produces electrons and holes in the CZT detectors and may cause their radiation-induced polarization at high fluxes similar to X-rays. Similar flux dependencies of electric field profiles and detector currents were observed for both types of excitations [10].…”

Section: Introductionmentioning

confidence: 99%

Infrared LED Enhanced Spectroscopic CdZnTe Detector Working under High Fluxes of X-rays

Pekárek

Dědič

Franc

et al. 2016

Sensors

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This paper describes an application of infrared light-induced de-polarization applied on a polarized CdZnTe detector working under high radiation fluxes. We newly demonstrate the influence of a high flux of X-rays and simultaneous 1200-nm LED illumination on the spectroscopic properties of a CdZnTe detector. CdZnTe detectors operating under high radiation fluxes usually suffer from the polarization effect, which occurs due to a screening of the internal electric field by a positive space charge caused by photogenerated holes trapped at a deep level. Polarization results in the degradation of detector charge collection efficiency. We studied the spectroscopic behavior of CdZnTe under various X-ray fluxes ranging between 5×105 and 8×106 photons per mm2 per second. It was observed that polarization occurs at an X-ray flux higher than 3×106 mm−2·s−1. Using simultaneous illumination of the detector by a de-polarizing LED at 1200 nm, it was possible to recover X-ray spectra originally deformed by the polarization effect.

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Laser-Induced Transient Currents in Radiation Detector Materials

Suzuki¹

2021

Advanced Materials for Radiation Detection

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Flux-dependent electric field changes in semi-insulating CdZnTe

Cited by 19 publications

References 13 publications

Temporal and temperature evolution of electric field in CdTe:In radiation detectors

Temporal and temperature evolution of electric field in CdTe:In radiation detectors

Infrared LED Enhanced Spectroscopic CdZnTe Detector Working under High Fluxes of X-rays

Laser-Induced Transient Currents in Radiation Detector Materials

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